Answer:
I think it is b. to determine how the vice president was chosen
Step-by-step explanation:
I looked it up and the internet said this
"Passed by Congress December 9, 1803, and ratified June 15, 1804, the 12th Amendment provided for separate Electoral College votes for President and Vice President, correcting weaknesses in the earlier electoral system which were responsible for the controversial Presidential Election of 1800." -
Document for December 9th: 12th Amendment